Why Convert Square Kilometers to Square Miles?
Converting between square kilometers (km²) and square miles (mi²) is one of the most common area conversions. Whether for engineering, cooking, travel, or science, knowing how to quickly convert km² to mi² saves time and prevents errors.
Area conversions between km² and mi² are critical in real estate, agriculture, and urban planning. When buying property internationally, apartment sizes are quoted in square meters in most countries but square feet in the US. Agricultural land in China uses mu (亩), while Western countries use hectares or acres. Understanding area conversion helps compare real estate prices across different markets accurately.
How to Convert Square Kilometers to Square Miles
To convert square kilometers to square miles, use the following formula:
mi² = km² × 0.3861021585
Example: 1 km² = 0.3861021585 mi²
For example, 5 km² = 1.930510793 mi², 10 km² = 3.861021585 mi², and 100 km² = 38.61021585 mi². Our calculator above performs this conversion instantly with full precision — no rounding errors.
Common Use Cases
- Small town area: 1 km² = 0.3861021585 mi²
- City area of Shanghai (urban core): 603 km² = 232.8196016 mi²
- City area of Los Angeles: 1221 km² = 471.4307356 mi²
- Area of Cyprus (island): 9597 km² = 3705.422416 mi²
Common Mistakes to Avoid
- Square vs linear: When converting area, the factor is squared. If 1 m = 3.281 ft, then 1 m² = 10.764 ft² (3.281²), not 3.281 ft².
- Hectare vs acre precision: 1 hectare = 2.471 acres. Many people round to 2.5, which introduces 1.2% error — significant for land transactions.
- Regional units: Asian countries use unique area units (畝/mu in China, 坪/pyeong in Korea/Taiwan). Don't assume universal standards.
Pro Tips
- Memorize the factor: 1 km² = 0.3861021585 mi². For quick mental math, remember this base conversion.
- Quick reference: 5 km² = 1.930510793 mi² · 10 km² = 3.861021585 mi² · 25 km² = 9.652553964 mi² · 50 km² = 19.30510793 mi² · 100 km² = 38.61021585 mi²
- Bookmark this page: Save this converter for instant access. It works offline once loaded — no internet needed.
Square Kilometers to Square Miles Conversion Table
| km² | mi² |
|---|---|
| 0.01 km² | 0.003861021585 mi² |
| 0.1 km² | 0.03861021585 mi² |
| 0.5 km² | 0.1930510793 mi² |
| 1 km² | 0.3861021585 mi² |
| 2 km² | 0.7722043171 mi² |
| 5 km² | 1.930510793 mi² |
| 10 km² | 3.861021585 mi² |
| 20 km² | 7.722043171 mi² |
| 50 km² | 19.30510793 mi² |
| 100 km² | 38.61021585 mi² |
| 500 km² | 193.0510793 mi² |
| 1000 km² | 386.1021585 mi² |
All values in this table are mathematically exact per NIST SP 811.